Now another phenomenon has appeared. Might be related to the above, and there is a workaround.
In WinXPpro using XP Power Toys desktop, when at least two instances of WinSCP are running, one of the instance's window will "reduce" in size until it reaches (apparently) the minimum size. Only the title bar with "WinSCP" and the title bar's buttons are visible.
This window will now not resize.
If this window closed last, then WinSCP will no longer properly launch, and must be uninstalled (complete) and re-installed before it will properly launch.
(This is the workaround) If the remaining "un-shrunk" window is closed last, there are no problems at WinSCP's next launch.
I wouldn't call this anything but a minor bug, but I thought you would be interested. 8)